Measles virus (MV) causes the death of about a million children yearly, with fatality rates estimated to be approximately 5-10% in developing countries (Measles Virus, pp 13-33, ter Meulen and Billeter (ed.), Springer-Verlag, Berlin, 1995). Measles often is accompanied by immune suppression, which is thought to contribute to the susceptibility to secondary infections that account for most of the morbidity and mortality associated with the disease (Borrow and Oldstone (1995) Curr. Top. Microbiol. Immunol. 191:85-100). A live attenuated strain of the measles virus, MV-Edm, has been used to vaccinate against the disease and its sequelae (Duclos and Ward (1998) Drug Saf. 19:435-454). MV-Edm is not pathogenic. Vaccine recipients experience mild or no symptoms, and adverse consequences are extremely rare (Measles Virus, pp. 167-180, Fields, Knipe, et al. (ed.), Raven Press, Ltd., New York, 1995). Viruses such as MV have potential therapeutic use in treatment of human malignancies (see, e.g., PCT patent application Ser. No. PCT/US01/42259), but can result in immune suppression.